Method for producing electrically conductive heated glass panels

ABSTRACT

An electrically conductive heated glass panel assembly, control system, and method for producing panels are provided to warm objects and to insure unobstructed viewing through glass by removing moisture. An integrated connection circuit interconnects glass sheets, which have a low emissivity conductive coating deposited thereon. The circuit includes copper bus bars that are disposed onto the conductive coating through the use of a circularly rotating or an inline heating head and mask apparatus. A metallic tab, which extends from the glass sheet&#39;s peripheral edge, is disposed onto each conductive metal bus bar for external electrical connectivity. Two types of glazing channels are offered to interconnect multiple panels to external circuits and controls. A solid-state controller may be provided to obtain sensor control signals so as to drive a triac circuit that provides current flow through the panel for the desired heating.

This application claims the benefit, under 35 U.S.C. § 119(e), of U.S.Provisional Patent Applications Ser. No. 60/339,409, filed Oct. 26, 2001under 35 U.S.C. § 111(b), and Ser. No. 60/369,962, filed Apr. 4, 2002under 35 U.S.C. § 111(b), which applications are incorporated herein intheir entirety.

This application is a divisional application of and claims benefit,under 35 U.S.C. § 120, of pending U.S. patent application Ser. No.10/256,391, filed Sep. 27, 2002, which application is incorporatedherein in its entirety.

BACKGROUND OF THE INVENTION

The present invention generally relates to electrically conductiveheated glass panel assemblies and control systems, for warming objectsand for the removal of moisture on such glass panel assemblies. Moreparticularly, the present invention relates to regulating the flow ofcurrent in low emissivity (low E) conductive metal oxide coatings oninsulated glass (IG) panels and laminated structures. Most particularly,the present invention deals with the electrical connectivity toinsulated glass panels, laminated structures, and combinations thereof.

At the present time, heating, cooking, moisture control, and theelectrical control of such processes and activities do not take fulladvantage of the potential of the use of coated glass. In general,utilizing thin-film coatings to produce heat in a glass panel is anestablished concept. However, in the past, the film depositiontechniques, such as those used in spray coating, were not precise, whichresulted in non-uniform coatings and consequently imprecise heating.Recently, the depositing of the coatings has improved, for example,through the use of chemical vapor deposition (CVD), but the electricalcontrol of and connectivity to the coatings has not.

An application of heated glass that has seen these changes over the lastthirty years is, for example, the commercial refrigerator and freezerdoors in supermarkets, where a tin oxide coating is disposed on one ofthe interior surfaces of an IG panel and where an electric current isdissipated in the tin oxide to provide heat to raise the glasstemperature above the dew point. On such doors, the heat eliminates theformation of condensation, so that employees and customers can view therefrigerator/freezer contents after individuals have opened and closedthe doors.

However, non-uniform coatings and traditional electrical control methodsresult in wasted energy, produce hot and cold spots on the glass, andcan result in safety hazards should the glass break and expose thecurrent-carrying film. This approach could benefit from controlopportunities that exist using the current state of control technology.

For transportation applications, where heated windows and mirrorsprovide drivers and occupants of land, air, and water vehicles unimpededviewing by the removal of condensation, breakage of the electricallyheated glass panels can also result in electrical safety problems.Underwriters Laboratories (UL) has expressed interest in improving thebreakage of electrically heated glass panels and consequently theexposure of live electrical conductors within the glass.

In convenience stores and delicatessens, sandwiches and other food itemsare kept warm in glass enclosed food warmers, through the use of baseelectrical element heaters. The use of glass enclosures does allow thecontents to be seen, but the use of only base electrical ribbon elementheaters does not allow for radiant heating techniques that would beadvantageous for the warming of food items from an area above the fooditems.

Commercial buildings, sports stadium skyboxes, sloped glazing in atria,canopies, and general fenestration applications, could benefit from theuse of electrically heated glass panels, but the underlying reason forthe reluctance to adopt these technologies in architectural applicationsis the lack of an integrated connection circuit and a systems approachto these applications. Expanding the adoption of these technologies,however, is hampered by the complexity of safely, reliably, and costeffectively combining glass and electricity.

There have been many methods advocated to electrically control heatedglass panels. Among them are: direct connection to 120V AC power, use ofstep-down transformers, resistor-capacitor (RC) networks, triacs, andcontrol circuits that directly drive resistive loads. All of theseapproaches have their benefits and also their disadvantages.

Some of the problems that must be overcome by the electrical controlsare: (a) electrical shock potential, (b) circuitry components releasingsignificant heat to the overall system, (c) overload of the integratedconnection circuits that supply the power to the panels, (d) bulkinessof the parts used in the control method, (e) lack of mounting space forthe parts, (f) electrical interference generated by the control method,(g) lack of predictability and complexity of the control method, and (h)overall serviceability and costs.

The RC network approach that is taught in U.S. Pat. No. 5,852,284 toTeder et al. uses an RC circuit in series with the conductive coating onthe glass to match the power supply with the characteristics of theglass assembly. Typically the value of the capacitor can be chosen forthe desired power density via known electrical engineering calculations.In this method, the capacitor functions by changing the phase anglebetween the voltage and current of the applied AC voltage, henceregulating the power dissipation.

Disadvantages of this method are that capacitors of the required valueare: (1) physically large and may be expensive, (2) when a capacitorfails, the full line voltage may be applied across the coated glass, (3)there is no integrated protection using such a method, so over-currentprotection must be provided, (4) handling many different applications isproblematic, such that either a stock of a large number of differentvalues of capacitors would be required or a large number ofseries-parallel networks must be constructed, which can also complicatethe issues of required space and cost, and (5) the varying electricalphase angle may present power quality problems.

The use of triacs has shown promise as a way to vary the current that isapplied to electrically coated sheets of glass. Examples of triac useare U.S. Pat. No. 4,260,876 to Hochheiser and U.S. Pat. No. 5,319,301 toCallahan et al. However, this use must overcome the negative effects ofthe triacs generating high peak currents, high harmonic distortion, andelectromagnetic interference (EMI).

The use of electrical control circuits to operate the triacs, which inturn controls the current through the electrically conductive heatedglass panel assembly and control systems, has the potential to minimizethese negative effects, but to-date it has not been able to accomplishthat task. Consequently, the application of triacs has not fully beenable to solve the aforementioned problems in the control of electricallyconductive heated glass panel assembly systems.

Also, the interconnections between the parts of an electricallyconductive heated glass panel assembly and control system have typicallybeen treated as individual parts and not as part of an overall system.In some cases, the bus bars have been screen-printed or fired conductivesilver frits. These are difficult and expensive to print and difficultto solder external leads to, where special solder is required.

Further, various metallic tapes, including copper, have been attached toglass using adhesives but these connections exhibit poor adhesion to theglass. Also, rigid electrical terminations at the edge of the glassresult from these methods of applying the bus bars, which makes themvulnerable to mechanical flexing, can expose them to condensation, andtypically are expensive.

U.S. Pat. No. 2,235,681 to Haven et al., teaches the attaching of metalbus bars to a glass sheet as it applies to structural solder elementsbut not for electronic control systems.

Producers of crystalline solar cell technology (also referred to hereinas photovoltaic technology) have been seeking ways to depositmetal-on-glass. U.S. Pat. No. 6,065,424 to Shacham-Diamand et al.,teaches thin metal film coatings sprayed onto glass by the use of anaqueous solution and subsequent annealing of the coatings. In U.S. Pat.No. 4,511,600 to Leas, a conductive metal grid is deposited atop acrystalline solar cell by the use of a mask and orifices (without theuse of gas or air pressure to impart dispersion or velocity to the metalparticles). The '600 patent also advocates the use of a powdered metalthat is heated to a molten temperature in a refractory crucible.

In U.S. Pat. No. 4,331,703 to Lindmayer, a conductive metal is flamesprayed onto a silicon solar cell. In U.S. Pat. No. 4,297,391, also toLindmayer, particles of a material are formed at a temperature in excessof the alloying temperature of the material and the silicon, and thenthe two are sprayed onto the surface of the glass at a distance, whichcauses the material and the silicon to firmly adhere to the surface. The'391 patent also teaches the use of a mask.

Currently, the control of electricity to electrically conductive glasspanels centers primarily on control of the heating elements and not onmonitoring system parts or the entire heating system for safety, powermatching, or the like. For wiring installation purposes of the glasspanels, it is common for holes to be drilled in the glass panels at thetime of manufacturing and in the framework at the time of installationas well as for termination of wiring that is done in the field.

When the assembly of the electrical panels is completed, some of thecontrols, wiring, and associated parts are visible to users of thesepanel systems. Since power supply matching for each application isstatically performed, the changing of system variables aftermanufacturing is, at best, cumbersome, while monitoring of systemoperating conditions is nearly nonexistent.

Termination of system wiring to existing facility electrical services,as well as on-site glazing operations, is not done with a total systemsapproach in mind. Thus those skilled in the art continued to seek asolution to the problem of how to provide a better electricallyconductive heated glass panel assembly and control system, and a methodfor producing the panels.

SUMMARY OF THE INVENTION

The present invention relates to depositing conductive metal on sheetsof dielectric substrate materials, for example, bus bars on a surface ofglass or on an electrically conductive coating that is disposed on amajor surface of a glass sheet, the bus bars being deposited by way of aheating head and mask apparatus. In conjunction, the present inventionrelates to depositing and electrically contacting metallic tabs, whichextend from the peripheral edge of the glass sheet to the metal busbars, to the bus bars thus allowing robust external electricalconnection to the electrically conductive coatings.

The glass sheet, so constructed, could be assembled with at least asecond glass sheet and a polymeric interlayer therebetween to form alaminated panel. In addition, the glass sheet could be assembled with atleast a second glass sheet and a T-shaped spacer-seal, an E-shapedspacer-seal, or the like disposed around a periphery therebetween toform an insulated glass panel.

Heated glass panels, as so described, may be mechanically andelectrically interconnected to form a heated glass panel assembly andcontrol system that would further comprise at least onecondition-sensing means capable of generating a condition signal, acurrent-switch, and a solid-state controller capable of reading thecondition signal for controlling the current-switch. As a result, thecurrent-switch would control electrical current in the heated glasspanel, thus controlling the desired heating of the heated glass panel.

The present invention employs methods of depositing a conductive metalbus bar on an electrically conductive coating that is disposed ondielectric substrate material, for example, a glass sheet, the methodsof depositing comprising: 1) if edge deletion is required, preciselythermally shocking or edge masking and heating a first area of thecoating with a coating heater, forming a residue of the coating in thefirst area, removing the residue from the first area with a coatingremover, and then regardless of whether edge deletion is required, 2)masking a second area of the coating with an inner mask and an outermask, where the second area is defined therebetween or by masking acentral area of the substrate sheet thus defining the second area asopposing edges, 3) heating the second area with a reducing flame, 4)feeding a conductive metal into a metal feeding and heating device, soas to melt the metal, and propelling particles of the molten metal ontothe second area.

Further objects and advantages of the present invention will be apparentfrom the following description and appended claims, reference being madeto the accompanying drawings forming a part of a specification, whereinlike reference characters designate corresponding parts of severalviews.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a is a schematic of an overview of an integrated connectioncircuit in accordance with the present invention;

FIG. 1 b is a schematic of an interconnection of an electricallyconductive heated glass panel and a first glazing channel in accordancewith the present invention;

FIG. 1 c is a schematic of an interconnection of an electricallyconductive heated glass panel and a second glazing channel in accordancewith the present invention;

FIG. 2 is a schematic of a current-switch circuit that employs triacs inaccordance with the present invention;

FIG. 3 is a cross sectional view of an installation of an electricallyconductive heated glass panel and a base setting block, within a firstglazing channel in accordance with the present invention;

FIG. 4 a is a cross sectional view of an electrically conductive heatedglass panel and a base setting block in a partially closed connectionposition in accordance with FIG. 3;

FIG. 4 b is a cross sectional view of an electrically conductive heatedglass panel and a base setting block in a fully clasped connectionposition in accordance with FIG. 4 a;

FIG. 4 c is a perspective view of an electrically conductive heatedglass panel and a connection clip in a fully clasped connection positionin accordance with FIG. 4 a;

FIG. 5 is a side view of electrical and mechanical connections of anelectrically conductive heated glass panel in accordance with thepresent invention;

FIG. 6 a is a side view of an interconnection of multiple electricallyconductive heated glass panels in accordance with the present invention;

FIG. 6 b is a side and bottom view of a wiring method showing a push-onconnector and interconnection wires in accordance with the presentinvention;

FIG. 7 is a cross sectional view of an installation of an electricallyconductive heated glass panel within a second glazing channel inaccordance with the present invention;

FIG. 8 a is a cross sectional view at a peripheral edge of an insulatedglass panel where a T-shaped spacer seal unit and a panel frame areemployed in accordance with the present invention;

FIG. 8 b is a cross sectional view at the peripheral edge of theinsulated glass panel where an E-shaped spacer seal unit is employed inaccordance with the present invention;

FIG. 9 is a cross sectional view at a peripheral edge of a laminatedglass panel in accordance with the present invention;

FIG. 10 a is a diagramatic view of a circularly rotating heating headand mask apparatus in accordance with the present invention;

FIG. 10 b is a diagramatic view of an inline heating head and maskapparatus in accordance with the present invention;

FIG. 10 c is a perspective view of a belt based inline heating head andmask apparatus in accordance with the present invention;

FIG. 10 d is a top plan view of the belt based inline heating head andmask apparatus of FIG. 10 c;

FIG. 10 e is a side plan view of the belt based inline heating head andmask apparatus of FIG. 10 c;

FIG. 11 is a perspective view of a warming oven in accordance with thepresent invention; and

FIG. 12 is a cross sectional view of an oven door panel in accordancewith the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention employs an integrated connection circuit 18, asshown in FIG. 1 a, where electrical current (I) passes through a coatingthat is disposed on a sheet of a dielectric material, for example, anelectrically conductive heated glass panel 20, to generate heat that canbe used for warming, cooking, moisture control, and the like. The panel20 may be realized within the present invention as a laminated panel 40,an insulated glass panel 30, or a combination thereof. The presentinvention has been found to apply to sheets that are dielectricsubstrate materials other than glass, for example, ceramic andglass-ceramic materials.

In order to control the electrical current (I) flowing through theelectrically conductive heated glass panel 20, a solid-state controller16, for example, a programmable application-specific integrated circuit.(ASIC) chip, would monitor inputs like a signal (S) from acondition-sensing means, for example, a condition sensor 21. Examples ofconditions that could be sensed by the condition sensor 21 include, butare not limited to, temperature, moisture, voltage, and current. Also,the signal (S) may be obtained from voltages taken across the bus bars22. If those voltage signals (S) are taken rapidly by way of thecontroller 16 the voltages can be converted into an indication of thetemperature of the panel 20.

Another way the present invention may obtain a signal (S) is through theplacement of a thermostatic switch (not shown) on a major surface 33 ofthe panel 20, wherein if the temperature of the surface 33 reaches afirst setpoint, the thermostatic switch is electrically conductive andif the surface temperature reaches a second setpoint the thermostaticswitch is electrically nonconductive.

Upon receiving the signal (S), the solid-state controller 16 mightrespond to the signal (S) by commanding various operations, likecontrolling a current-switch circuit 15, for example, a triac circuit 17shown in FIG. 2, to be operated in a zero-axis crossing manner.

Consequently, the solid-state controller 16 would precisely controlheating of the electrically conductive heated glass panel 20.

By operating the triac circuit 17 in the zero-axis crossing manner,problems such as harmonic distortion and electromagnetic interference(EMI) are overcome. Use of the zero-axis crossing manner also minimizescapacitive coupling and leakage current problems associated with usingdielectric material with electrical currents (I).

In the present invention, the current-switch circuit 15, under controlof the solid-state controller 16, would provide optical isolation (asshown in FIG. 2 by components U2 and U3) in the current-switch outputcontrol lines. In turn, this minimizes electrical interference tocontrol circuit 25, the electrically conductive heated glass panel 20,and external sensors and controls 28.

In addition, the solid-state controller 16 allows the present inventionto usefully integrate disparate parts of the electrically conductiveheated glass panel 20 in a more comprehensive manner than RC networksand other control methods can provide. This allows the solid-statecontroller 16 to more effectively control appliances, for example, aheating element, vehicles, or building functions by way of the externalsensors and controls 28, while employing wired or wireless devices.System variables are easily changed by a use of the solid-statecontroller 16.

Further, the solid-state controller 16 would provide impedance matchingfor the current-switch circuit 15, which would result in more completesystem safety by monitoring voltage and current levels that are too highand too low. This would protect users and system components, forexample, by shutting down associated equipment. Other forms ofelectrically conductive heated glass panel controls may not be able toprovide this capability.

Additionally, regarding glass breakage safety, the solid-statecontroller 16 is capable of monitoring the current (I) passing threw thecoating 44 on the panel 40. If the current (I) were to cease in thecoating 44 then the panel 40 may have broken. Also a strip switch 26 maybe applied that would be sealed within the laminated glass panel 40, asfurther illustrated in FIG. 9. If the uncoated glass sheet 32 were tobreak then the current (I) through the strip switch 26 would cease,wherein the solid-state controller 16 would sense a change in thecurrent (I), would cut off power to the damaged laminated glass panel40, and would signal users of the integrated control circuit 18 of suchan event, so as to keep the users from being exposed to an electricalshock and physical cuts due to broken glass.

By operating the current-switch circuit 15 in the zero-axis crossingmanner, the solid-state controller 16 does not require controllingcapacitors. This reduces cost, weight, and number of system components,which consequently reduces the necessary space to mount them. Inaddition, the solid-state controller 16 provides electrical isolationfor system components that other control circuits cannot provide and thesolid-state controller 16 provides power source conditioning, whichbetter manages electrical component requirements.

As a result, maintenance replacement inventories are simplified, fieldadjusting of system devices and set points are reduced, as well asassociated costs. Since the solid-state controller 16 can read internaland external system signals (S), precision control of glass temperaturescan be provided, system performance can be monitored, and early warningof system problems can be detected that other electrically conductiveheated glass panel control-methods cannot achieve.

To interconnect the electrically conductive heated glass panel 20 to thecurrent-switch circuit 15 and to interconnect a plurality ofelectrically conductive heated glass panels 20, a first glazing channel60 may be employed, as shown in FIG. 1 b. Panel setting blocks 35, thatare disposed on the electrically conductive heated glass panels 20, matewith base setting indentations 43 to provide mechanical mounting for theelectrically conductive heated glass panels 20.

Further, portions of metal foil 39 a, 39 b are disposed within theelectrically conductive heated glass panels 20, from a glass panelperipheral edge 37, up to a sight line 29, and onto metallic tabs 24.The metallic tabs 24 and foil 39 electrically connect to the firstglazing channel 60 by being clasped by connection clips 41, whichelectrically connect to channel conductors 27. Insulating sleeves 31 andthe channel conductors 27, provide means to allow the electricallyconductive heated glass panels 20 to be connected to additionalelectrically conductive heated glass panels 20. Note that the use ofmetal foil 39 as described here may be applied to other glazingchannels.

Consequently, the current-switch circuit 15 that controls the electricalcurrent (I) may allow the electrical current (I) to be conducted throughthe glazing channel 60, by way of the channel conductors 27 and theconnection clips 41. Since the connection clips 41 clasp the metallictabs 24, the electrical current (I) enters the electrically conductiveheated glass panels 20 and passes through bus bars 22 and coating 44,which is disposed on a coated glass sheet 34. As a result, heat isgenerated within the electrically conductive heated glass panels 20 forheating objects and removing moisture.

An alternative to the first glazing channel 60 of FIG. 1 b is a secondglazing channel 60′, illustrated in FIG. 1 c and with more detail inFIG. 7. The electrically conductive heated glass panel 20 ismechanically mounted to a channel frame 67 and electrically connected tothe metallic tabs 24 by way of spade connection 96 that is attached toan end of the channel conductor 27. The channel conductor 27 is in turnrouted through the channel frame 67 by way of a channel conduit 95 andconductor block 93 and then electrically and mechanically connected tothe interconnecting channel conductor 27 by conventional means. Glazingseal 23 is disposed in a second glazing channel cavity 59′ and in voidsthroughout the channel frame 67 to seal out moisture and dirt, and toprotect the parts of the second glazing channel 60′ from damage.

Consequently, the current-switch circuit 15 that controls the electricalcurrent (I) may allow the electrical current (I) to be conducted throughthe second glazing channel 60′. As a result, heat is generated withinthe electrically conductive heated glass panels 20 for heating objectsand removing moisture. Both glazing channels 60, 60′ would be applicablefor photovoltaic applications.

It may be noted that conventional type K thermocouples or possibly athin film thermocouple like that disclosed in U.S. Pat. No. 6,072,165 toFeldman (which is incorporated herein in its entirety) may be used fortemperature determination. An advantage of the present invention is thatprogramming the solid-state controller 16 with the coefficient ofresistance of the electrically conductive heated glass panel 20 andmomentarily sampling voltages across sets of bus bars 22, thesolid-state controller 16 could compare those voltages to predeterminedthresholds (a.k.a., setpoints) so as to determine the temperature of thepanel 20. Thus the temperature of the panel 20 may be controlled withoutthe use of any thermocouple.

By using the controller 16 along with the type K thermocouple, the filmthermocouple, or the voltage reading method temperature sensing, apanel, for example, one installed in a sport stadium box, would notoverheat, break, or cause damage, as other glass assemblies would.

The solid-state controller 16, the condition sensors 21, thecurrent-switch circuit 15, the metallic tabs 24, direct current powersupplies 14 that are illustrated in FIG. 1 a, along with conventionalwiring, insulating boots, terminal strips, direct current to alternatingcurrent inverter circuits, ground fault circuit interrupter (GFCI)circuit breakers, on-off alternating power source controls, connectionsto external sensors and controls 28, NEC electrical wiring terminationboxes and connecting wiring, the channel conduit 95, the conductorblocks 93, may all be placed in one or more of the panel frames 48,panel setting blocks 47, channel frames 67, or in conventional NECcontrol panels. This will result in advantageously placing the parts outof sight, while conserving space.

Referring to FIG. 3, there is shown a first glazing channel 60, which isan assembly of three subassemblies in accordance with an aspect of thepresent invention: (1) the laminated glass panel 40 (the insulated glasspanel 30 or combination laminated and/or IG panel may be employed aswell), (2) a base setting block 47, and (3) a glazing channel base 58.In FIG. 3, the laminated glass panel 40 is shown having the metallic tab24 and the metal foil 39 disposed within the interlayer 46, where themetal foil 39 is disposed from the sight line 29 to the glass panelperipheral edge 37 and onto the exterior portions of the metallic tabs24, so as to keep the metal foil 39 out of the sight of users.

As shown in FIG. 1 b, a portion of the metal foil 39 a that is disposedon a particular metallic tab 24 may not be in direct electrical contactwith another portion of metal foil 39 b, within the same laminated glasspanel 40. This separation of the portions of the metal foil 39 a, 39 bmay be required in order to allow the electrical current (I) to beconducted through one metallic tab 24 and its corresponding bus bar 22,the conductive coating 44, another bus bar 22 and its correspondingmetallic tab 24.

External to the laminated glass panel 40, both the metallic tab 24 andthe metal foil 39 are shown extending from the glass panel peripheraledge 37. The deposition of the metal foil 39 and the metallic tab 24, asdescribed, causes the two to be in electrical contact with each other,thus providing a measure of redundancy. In addition, FIG. 3 shows themetal foil 39 and the metallic tab 24 being mechanically clasped byopposing inside clasping surfaces 55 of a connection clip 41, theclasping by the clasping surfaces 55 being a result of a spring 52urging the connection clip 41 about a pivot 57.

The extension of the spring 52 is a result of a movement of theconnection clip 41 within the base setting block 47, wherein the basesetting block 47 is formed so as to define at least a widened portion ofa block cavity 51. As a result of the aforementioned movement, thelaminated glass panel assembly 40 and the base setting block 47 abut toform an assembly. Subsequently, the abutment of the laminated glasspanel 40 and the base setting block 47 are further abutted to a glazingchannel surface 53 that is positioned to define at least a portion of afirst glazing channel cavity 59 within a glazing channel base 58.

To further assure that the wiring of the laminated glass panels 40 ishidden from the view of the user and to allow moisture to drain out andaway from the laminated glass panels 40, wiring/drain holes 49 may beprovided in the glazing channel base 58, preferably at the time ofmanufacturing, so as to minimize the need to drill holes in thelaminated glass panels 40 during installation in a structure or thelike.

Unbonded areas (UBAs) may form on the aforementioned assembly, which canresult in: (a) moisture entering, (b) glass chipping, (c) glassswelling, and (d) electrical connections being adversely affected. Inthe present invention, a glazing seal 23 is preferably disposed inassembly voids to minimize the negative effects of UBA.

As illustrated in FIGS. 4 a–4 c, there is shown the laminated glasspanel 40 (the insulated glass panel 30 or combination laminated and/orIG panel may be employed as well) being brought into abutment andelectrical connection with the base setting block 47 and the connectionclip 41 in accordance with FIG. 3. FIG. 4 a shows a cross sectional viewof a partially closed connection clip 41 where the spring 52 is onlypartially extended. Also shown is the laminated glass panel 40approaching the base setting block 47, wherein the attached metal foil39 and metallic tabs 24 are about to be clasped by the partially openconnection clip 41 and its partially extended spring 52.

As the laminated glass panel 40 and the connection clip 41 move intofull attachment, the cross sectional view of FIG. 4 b shows the completeclasping of the metal foil 39 and the metallic tabs 24 by the connectionclip 41 along with the full extension of the spring 52. Also shown inthis view are the laminated glass panel 40 and the base setting block 47in full abutment.

FIG. 4 c is a perspective view in accordance with FIG. 4 a showingfurther details of the laminated glass panel 40 having the metal foil 39and metallic tab 24 fully clasped by the connection clip 41 whileshowing an extension of the channel connector 27 with insulating sleeve31 attached to the connection clip 41 at the pivot 57 of the connectingclip 41. The channel connector 27 along with the insulating sleeve 31,may act to interconnect a plurality of base setting blocks 47.Consequently, a plurality of laminated glass panels 40 would beinterconnected within the integrated connection circuit 18.

The above discussion on the interconnection of the laminated glass panel40, by way of the metal foil 39, the metallic tabs 24, the connectionclips 41, and the springs 52, in conjunction with the base setting block47, applies to glass solar panels as well.

Further, FIG. 5, in accordance with the present invention, shows a sideview of the electrical and mechanical connection of the laminated glasspanel 40 (the insulated glass panel 30 or a combination laminated and/orIG panel may be employed as well), where the metal foil 39 covers theelectrical connection for each metallic tab 24, thus providing themeasure of electrical redundancy, from within the laminated glass panel40, starting at the sight line 29, and then externally covering theextension of the metallic tabs 24.

Subsequently, the metallic tabs 24 mate with the connection clips 41,which are embedded in the base setting block 47, as shown in FIG. 1 b. Amechanical connection between the laminated glass panel 40 and the basesetting block 47 is achieved by a mating of one or more panel settingblocks 35 and one or more base setting indentations 43, as shown inFIGS. 1 b and 5.

In accordance with the present invention, the combination of FIGS. 6 aand 6 b illustrate how an interconnect 80 uses multiple panel wiring 90to interconnect multiple laminated glass panels 40. Channel conductors27 and push-on connectors 54, in combination with the metal foil 39 andthe connection clips 41 provide ease and redundancy to accomplish theinterconnection of the multiple laminated glass panels 40. Theseinterconnection means complement the use of the channel connectors 27and the insulating sleeves.31 for interconnecting multiple laminatedglass panels 40, as discussed above.

In addition, FIG. 6 a shows an application of a thermocouple 65, acircuit breaker 61, and a power switch 63, which act to monitortemperature conditions and to control power within the integratedconnection circuit 18. If the temperature of the laminated glass panel40 exceeds a setpoint temperature, as set within the circuit breaker 61,the flow of electrical current (I) will be terminated. The power switch63 is a manual means to also terminate the flow of the electricalcurrent (I), within the integrated connection circuit 18.

By incorporating the wiring of the laminated glass panel 40 into thebase setting block 47 and providing easy and redundant multiple panelwiring 90, the present invention eliminates the difficulty of makingelectrical connections. The hole drilling process into the glass sheet32 or coated glass sheet 34, prior to lamination, as is typically doneto expose the bus bars 22 for connection to the alternating currentpower source 19, is eliminated.

Instead, the present invention uses the metallic tabs 24 and metal foil39, described herein that are easily incorporated into the integratedconnection circuit 18. The wiring connections between parts of theintegrated connection circuit 18 may have flexible boots (not shown)encasing the connections, and the glazing sealant 23 may be used toattach the flexible boots to the glass panel peripheral edge 37, so asto minimize mechanical wear and accumulation of moisture. The flexibleboots, with enclosed wiring, may be dressed through conventional gasketsor sealed with sealant and then terminated in National Electrical Code(NEC) electrical wiring boxes.

Typically, the internal integrated connection circuit 18 will becompleted during manufacturing, so as to minimize the need for on-siteelectricians doing system wiring at the time of field installation.Instead, electricians would need to simply verify correct connection andterminate electrical load wiring at the time of field installation.Glaziers would typically be the primary installers of the electricallyconductive heated glass panel 20 by glazing the wiring 90, boots, frames48, and panels 30, 40, which should preserve manufacturing integrity andimprove reliability of the electrically conductive heated glass panels20.

FIG. 7 shows a cross sectional view of an installation of a singlelaminated glass panel 40 within a second glazing channel 60′. However,it can be appreciated that multiple laminated panels 40, multipleinsulated glass panels 30, or combinations of the panels 30, 40 could berealized in this aspect of the present invention. Also, these panels 20may be used in heated glass, switchable glass, and photovoltaicapplications. In addition, this aspect may be applied to architecturalglazing as well as cladding material.

As shown, the laminated glass panel 40, along with various parts of thesecond glazing channel 60′ are disposed on the channel frame 67. Aportion of the laminated glass panel 40 is shown being disposed withinthe second glazing channel cavity 59′ and abutting the channel frame 67,wherein the metallic tab 24 extends beyond the periphery of the panel40. Mechanically and electrically disposed on the metallic tab 24 is aspade connector 96, which is mechanically and electrically disposed onan end of channel conductor 27. The channel conductor 27 is shown beingdisposed within the channel conduit 95, which passes through a coupler91 to the conductor block 93. Within the conductor block 93 a second endof the channel conductor 27 may be mechanically and electricallydisposed on the multiple channel wiring 90 (shown in FIG. 6 b) or byconventional means in the art on the channel conductors 27 that are partof the interconnect 80 (shown in FIG. 6 a).

Multiple connections, as FIG. 7 illustrates, may be provided in each ofthe glazing channels 60, 60′, in order to assure the measure ofredundancy of the electrical connectivity to the panels 30, sincemaintenance and removal of the panels 30 would be tedious and costly.

FIG. 8 a illustrates a cross sectional view at the glass panelperipheral edge 37 of the insulated glass-panel 30 where the glass sheet32 and the coated glass sheet 34 are separated by an insulating T-shapedspacer-seal 42 (conventionally known as a seal unit) that is disposedaround the periphery 37 therebetween. The insulating T-shaped spacerseal 42 could comprise foamed silicone. In addition, an adhesive sealant36 is disposed on surfaces of the insulating T-shaped spacer seal 42where the insulating T-shaped spacer seal 42 makes contact with theglass sheet 32 and the coated glass sheet 34. The adhesive sealant 36functions to maintain a specified gaseous concentration, preferably atatmospheric pressure, however, any desired pressure may be maintainedwithin a space 38 between the glass sheet 32 and the coated glass sheet34.

To seal out contaminants and to protect the seal units, a panel frame 48may be provided that covers the entire seal unit, as it is disposedaround the periphery of the insulated glass panel 30. As so described,the glass edge sealing method may not require that the electricallyconductive coating 44 be removed from the coated glass sheet 34, whichmay eliminate the need for “edge deletion” and associated costs.

FIG. 8 b illustrates a cross sectional view at the glass panelperipheral edge 37 of an insulated glass panel 30′ in accordance withthe present invention. The application shown in FIG. 8 b is similar tothat shown in FIG. 8 a with the exception that the glass sheet 32 andthe coated glass sheet 34 are separated by an insulating E-shaped spacerseal 45 (seal unit) that is disposed around a periphery therebetween.The insulating E-shaped spacer seal 45, having a seal cavity 69, couldcomprise silicone. The seal cavity 69 may be used as a wiring chase forthe placement of interconnecting wiring and for placement of adesiccant, which is used to remove moisture that enters the space 38.The panel frame 48, as shown in FIG. 8 a, if so required, may bedisposed around the E-shaped spacer seal 45 of FIG. 8 b.

Some preferred applications of the insulated glass panels 30 of FIGS. 8a and 8 b would be as architectural panels, such as in glazings forcommercial buildings, sports stadium skyboxes, sloped glazing in atria,canopies, general fenestration applications, architectural solar panelsand other photovoltaic applications, where the removal of condensationon the surface of glass panels would be accomplished by heating thepanels to above a dew point.

If so needed, these applications could utilize the integrated connectioncircuit 18 of FIG. 1 a, where the current-switch circuit 15 would belike that shown in FIG. 2. Due to its design, the current-switch circuit15 allows the alternating current (I) to be optically isolated from thecontrol circuit 25, wherein the solid-state controller 16 operates thecurrent-switch circuit 15 in the zero-axis crossing manner. Thetemperature and/or moisture condition sensors 21 would monitor ambientconditions and communicate these conditions to the solid-statecontrollers 16, in order for the solid-state controllers 16 to commandthe current-switch circuit 15 to provide the alternating current powersource 19 to the electrically conductive heated glass panels 20 for thedesired heating of the electrically conductive heated glass panels 20.

In addition to controlling the heating of the insulated glass panels 30,the solid-state controllers 16 would monitor the current (I) passingthrough the conductive strip switches 26 that would be mounted in theinsulated glass panels 30. In the event that the conductive strip switch26 opens, which could be due to the glass sheet 32 breaking, the currentto that electrically conductive heated glass panel 20 would be stoppedby the solid-state controller 16, which would remove the possibilitythat individuals would be exposed to live electrical hazards.

A major advantage of using IG panels 30 with low-E coating 44 as theheating element (as opposed to directly connected resistance coatings)is the large improvement in energy efficiency, where 25% to 30%improvement can be realized, while operating at comparable surfacetemperatures. These results are due to the improved thermal R-valuesthat result from, for example, double or triple pane IG low-E panels 30.In addition, if the space 38 is filled with argon or krypton, in placeof air, the resulting heating from the IG panels 30 is equivalent tobase board or other electrical resistance heating methods. Addedadvantages of the use of low-E IG panels 30 are an allowance of morehumidity in the room before the onset of condensation and usability ofthe area adjacent to the windows in extremely cold climates.

Warming shelves 106, 108 and other applications of the panels 30 thatwould be made as those shown in FIGS. 8 a, 8 b would have the followingadvantages: a) the deletion of the coating 44 on the edge 37 isunnecessary, b) superior edge protection is provided by the polymericT-shaped seal 42 and E-shaped seal 45, and c) the wire chase provided bythe seal cavity 69 of the E-shaped seal 45 facilitates dressing of thechannel conductors 27.

FIG. 9 illustrates a cross sectional view at the glass panel peripheraledge 37 of the laminated glass panel 40, in accordance with the presentinvention. The electrically conductive coating 44 is deposited onto amajor surface 33 of a glass sheet 32 resulting in the formation of thecoated glass sheet 34. In turn, the bus bars 22 are deposited onto theelectrically conductive coating 44.

Further, the metallic tab 24 is disposed on the bus bar 22, where aportion of each metallic tab 24 extends beyond the peripheral edge 37 ofthe laminated glass panel 40. Subsequently, the metal foil 39 isdisposed on and in electrical contact with the metallic tab 24, whilealso being disposed on and in electrical contact with the coating 44from the peripheral edge 37 of and within the laminated glass panel 40,up to the sight line 29. To complete an assemblage of the laminatedglass panel 40 thus described, the parts so stated, are brought togetherwith the glass sheet 32 while the interlayer 46 of polymeric material isdisposed therebetween. The interlayer 46 of polymeric material maycomprise polyvinyl butyral (PVB).

Some of the preferred applications of the present invention that woulduse the laminated glass panels would be as heated glass applications invehicles, aircraft, vessels, and the like, where the removal ofcondensation and moisture could be achieved on windows, mirrors, andglass parts.

Photovoltaic laminated panels, which absorb light energy inphotosensitive material that is disposed on the coated glass sheet 34,pass the absorbed energy through the bus bars 22 and metallic tabs 24,in a way similar to that of the present invention.

Another application of a laminated panel 40 would be as an automotiverear window defogger where the panel 40 would replace the individualheater wires. The present invention would provide an invisible, faster,and more even heater replacement for the current heaters.

Further, results from testing indicate that when the panels 30, 40 ofthe present invention are used in various applications that currentlyuse coil, wire type, and parallel resistance heaters, 40% less energy isrequired to power the panels 30, 40. This is due in part to the low-Eproperties, the placement of the coating 44, and the uniformity of thecoating. Rear window defoggers and cooking heating elements benefit fromthis coating heater design.

In addition to glass substrate material, it has also been found that thepanels 30, 40 of the present invention may be realized by the use ofceramic and glass-ceramic substrate materials. The coating 44, bus bars22, and metallic tabs 24 are deposited equally as well as on glass andthat certain applications, for example, cooking and warming, may realizeaesthetic and cost benefits from the use of ceramic and glass-ceramicmaterials.

The laminated glass panels 40, as shown in FIG. 9, could be appliedwhere the integrated connection circuit 18 that is shown in FIG. 1 a,would use moisture and temperature condition sensors 21 to send signals(S) to the solid-state controllers 16, which in turn would communicatewith the current-switch circuit 15. The result of the current (I)flowing through the electrically conductive heated glass panel 20 is toheat the glass and mirrors, so as to remove moisture and condensationfrom the electrically conductive heated glass panel 20.

In addition, through the use of the solid-state controller 16, varyingpower levels could be provided to achieve functions like defogging anddeicing, where more power is provided for deicing. The voltage andcurrent condition sensors 21 may also be applied to sense glass breakageby the use of the conductive strip switches 26. With the presentinvention, the solid-state controller 16 may be used in a vehicle tocontrol various electrically conductive heated glass panels 20 having avariety of sizes and geometries to maintain, for example, all such glasspanels 20 at one temperature or each glass panel 20 at a differenttemperature.

With the current-switch circuit 15 being operated in the alternatingcurrent, zero-axis crossing manner, those vehicles, for example,automobiles, that only have a direct current power source, would requireconventional inverter circuitry to generate the alternating current thatis needed for the current-switch circuit 15. However, other vehicles andvessels, for example, emergency vehicles, fire trucks, ships, yachts,trains, and large earth moving vehicles, may have on-board alternatingcurrent power sources 19 that would not require the conventionalinverter circuitry and could be connected directly to the presentinvention's integrated connection circuit 18, as illustrated in FIG. 1a.

Further applications of the laminated glass panels 40 would have thepresent invention being utilized in commercial refrigerator/freezer doorapplications, where the removal of condensation on the surface of thelaminated glass panel 40 that is exposed to the cold air inside of therefrigerator or freezer would be accomplished by heating the laminatedglass panel 40 to a temperature above the dew point. These applicationswould utilize the integrated connection circuit 18 of FIG. 1 a, thelaminated glass panel 40 of FIG. 9, and the triac circuit 17 of FIG. 2.

Temperature and/or moisture condition sensors 21 would monitor ambientconditions and communicate these conditions to solid-state controllers16, which in turn command the current-switch circuit 15 to conductalternating current to the laminated glass panels 40, which wouldsubsequently heat the laminated glass panels 40, thus removingcondensation or other forms of moisture.

In addition to controlling the heating of the laminated glass panels 40,the solid-state controllers 16 would monitor current (I) passing throughthe conductive strip switches 26 that are mounted on coated glass sheets34. In the event that a conductive strip switch 26 opens, which could bedue to a particular laminated glass panel 40 breaking, the current tothat laminated glass panels 40 would be disrupted, hence removing thepossibility that individuals would be exposed to live electricalhazards. Since the solid-state controller 16 would be monitoring theconductive strip switches 26, it would sense that a particularconductive strip switch 26 had opened and would alert necessarypersonnel.

Two problems that arise with supplying electrical current to banks ofrefrigerator/freezer doors that the use of solid-state controllers 16would overcome, are: (1) the precise electrical control of the uniformlow E heating coatings 44 that should result in uniform heating of thelaminated glass panels 40 of the banks of refrigerator/freezer doors and(2) the synchronization of the current-switch circuit 15 switching toovercome peak current problems.

Because a bank of laminated glass panels 40 presents a large demand forpower, solid-state controllers 16 would be used to provide powerdemand-based control to avoid brown outs, power peak monitoring tocontrol kilowatt usage costs, and “turning back” of the supply of powerin off-hours to also control kilowatt usage costs. Condition sensors 16,other than temperature and moisture, for example, voltage and current,would be used to signal the solid-state controllers 16 for commanding avariety of conventional operations.

Note that the use of electronic controls with both IG panels 30 andlaminated panels 40 of the present invention result in higher heatingefficiency while using less power than conventional panels and whileproviding greater safety. This is due to the use of low emissivitycoated glass that places the heating element in an advantageous positionwith respect to the user and items being heated, and provides for lesselectrical noise generation.

FIG. 10 a, which involves the deposition of the bus bars 22 onto thecoating 44 that is deposited on the glass sheet 32, illustrates adiagramatic view of a circularly rotating heating head and maskapparatus 50 in accordance with an aspect of the present invention. Thebus bars 22, as shown in FIGS. 1 a, 1 b, and 1 c, function toelectrically connect the metallic tabs 14, which are the exteriorconnections for delivering the electrical current (I) to the coating 44of the glass panels 20. As a result, the current (I) supplied to thecoating 44 causes the coating 44 to dissipate heat.

FIG. 10 a illustrates the deposition of bus bars 22 on the coated glasssheet 34, which may be deposited through the use of improved depositionmethods in accordance with further aspects of the invention. Forexample, the coating deposition may comprise chemical vapor deposition,where the coating 44 is deposited onto the dielectric substratematerial, for example, the glass sheet 32. The coated glass sheet 34 maythen be exposed to a preheat zone 70 upstream and, if “edge deletion” isrequired, the conveyor 88 transports the coated glass sheet 34 to acircular edge mask 66. While moving within the circular edge mask 66, afirst area 92 of the coated glass sheet 34 is heated by a coating heater76. The coating heater 76 could comprise, as examples, an oxyacetyleneburner, a plasma device, an electric arc gun, or a flame spray gun.

In the case of the electric arc gun, electrical current is conductedthrough metal wires that are fed into the electric arc gun in order tomelt the metal wire. In all of the alternatives for the coating heater76, very high velocity airflow entrains and accelerates the molten metalparticles to ensure good adhesion.

In the first area 92, temperatures up to and about 1300 degreesFahrenheit may be attained in order to heat, thermally shock, andevaporate the electrically conductive coating 44.

Edge deletion may also be achieved without the use of the edge mask 66.This may be accomplished through precise placement of the heat andthermal control and set up of the coating heater 76, such that thecoating 44 is precisely thermally shock heated and evaporated. Either ofthese processes may be required for the IG panels 20 (shown in FIGS. 8 aand 8 b) to establish a better surface for sealing in the atmospherewithin the space 38.

By either method, a residue of the electrically conductive coating 44 isformed and may, subsequently, be removed by a coating remover 68, which,for example, may be a buffer or a burnishing tool. The coating remover68 may be required for the IG panels 20 (shown in FIGS. 8 a and 8 b) toestablish a better surface for sealing in the atmosphere within thespace 38. As a result, this process produces a deleted edge 71, as shownin FIG. 10 a.

Next, as FIG. 10 a also illustrates, the coated glass sheet 34 isconveyed to a circular inner mask 72 and a circular outer mask 74 wherea second area 94 of the coated glass sheet 34 is defined therebetweenand where dimensional control of the placement, thickness, tapering, andheight of the bus bars 22 is achieved. First a reducing flame 78 heatsthe second area 94 in a stoichiometric atmosphere, where oxidation of amolten metal 64 is controlled during bus bar 22 deposition, while notfracturing or de-tempering the coated glass sheet 34. The reducing flame78 could comprise oxyacetylene or hydrogen. As a result, the second area94 is taken to a temperature of about 500 degrees Fahrenheit.

Subsequently, a metal feeding and heating device 62, which is suppliedby gas one 82, gas two 84, and gas three 86 feeds conductive metal 56,preferably in the form of a wire (however, the conductive metal could befed as a powder or in other forms), melts the conductive metal 56, andthen propels and impinges particles of the molten metal 64 in apredetermined manner, for example, a uniform manner, onto the secondarea 94. The metal feeding and heating device 62 preferably comprises aplasma gun, while the three gases 82, 84, and 86 preferably compriseoxygen, air, and acetylene, and the conductive metal 56 preferablycomprises copper.

This operation results in the bus bars 22 being uniformly formed on, andadhering strongly to, the electrically conductive coating 44. Theformation of the bus bar 22 occurs, for example, near the glass panelperipheral edges 37, before the laminated glass panel 40, as shown inFIG. 9, or the IG panels 30 and 30′, as shown in FIGS. 8 a and 8 b, arefully assembled.

Added advantages of the circularly rotating heating head and maskapparatus 50 are that its rotation and size allow for: (1) dissipationof built up heat, (2) the excess molten metal 64 to be scraped, brushed,or blown clean, and (3) accurately depositing the molten metal 64 ontothe electrically conductive coating 44 so as to shape the bus bars 22.The shaping of the bus bars 22, if so preferred, may be tapered towardthe glass panel peripheral edge 37 and/or tapered on end, as well.

The result of these steps is the production of conductive metal bus bars22 that are uniformly deposited and have good mechanical bonding to theelectrically conductive coating 44, which makes them robust for externalconnectivity. In addition, the bus bars 22 possess good ohmicconductivity themselves and also in relation to the electricallyconductive coating 44.

Further, the circularly rotating heating head and mask apparatus 50accurately controls the thickness of the resulting copper bus bars 22,so that the thicker the bus bars 22, as shown in FIGS. 1 a and 1 b, thehigher the electrical current (I) that can be conducted through the busbars 22, which consequently provides higher electrical current (I) thatcan be supplied to the glass panel 20 or plurality thereof. In the caseof electrically conductive heated glass panels 20, the higher theelectrical current (I) that can pass through the electrically conductiveheated glass panels 20 the higher the heat that can be dissipated by theelectrically conductive heated glass panels 20. Also, the use of copperas the bus bar 22 material is less expensive than silver. However, thepresent invention may be practiced where silver or other conductivemetals comprise the bus bar materials.

An additional advantage of this process is that it allows the bus bars22 to be deposited after thermal tempering of the electricallyconductive heated glass panels 20. Although not wishing to be bound byany theory, it is believed that there is no alloying of the molten metal64, for example, copper, with the electrically conductive coating 44,since the electrically conductive coating 44 is highly chemicallyinactive and stable. The electrically conductive coating 44 preferablycomprises tin oxide. It has also been found that the deposition of theconductive metal, for example, copper, bus bar 22 will also adherestrongly to the coating 44 as it is disposed on ceramic or glass-ceramicsubstrates.

To form the bus bars 22, the circularly rotating heating head and maskapparatus 50 of the present invention does not use an aqueous solution.Instead, it heats and shapes the bus bars 22 onto the electricallyconductive coating 44 by melting the conductive metal 56, and impartingpressure, through the gasses one 82, two 84, and three 86, to impinge,at a high velocity, the molten metal 64 onto the heated and maskedsecond area 94 on the electrically conductive coating 44.

Further, the metallic tabs 24 may then be readily conductively affixedto external wiring 27 as part of the integrated connection circuit 18.The panel 20, as so constructed may be used for cooking appliances, forexample, a heating (conventionally known as a “burner”) element. The busbar deposited panel 20, as thus described, may also be used to form IGpanels 30, laminated panels 40, or combination thereof.

Illustrated in FIG. 10 b is an inline heating head and mask apparatus50′ that is also capable of edge deletion and capable of disposing thebus bar 22 on the coated glass sheet 34. If edge deletion is required,the coated glass sheet 34 moves on the conveyor 88 so that the edge ofthe coated glass sheet 34: a) may be preheated in the preheat zone 70,b) be thermally shocked at the first area 92, and c) have the coating 44removed by a coating remover 68, which, for example, may be a buffer ora burnishing tool, d) is formed into the deleted edge area 71. Thisprocess is the same as that described above for the circularly rotatingheating head and mask apparatus 50, with the exception that an inlineedge mask 66′ replaces the circular edge mask 66.

Note that edge deletion may also be achieved by the apparatus 50, 50′without the use of the edge masks 66, 66′. This may be accomplishedthrough precise placement of the heat and thermal control, and set up ofthe coating heater 76, such that the coating 44 is precisely thermallyshock heated. This process may be required by the IG panels 30 (shown inFIGS. 8 aand 8 b) to establish a better surface for sealing in theatmosphere within the space 38.

As the coated glass sheet 34 moves further on the conveyor 88, the busbar 22 can be disposed on the coating 44 in the same manner describedabove for the circularly rotating heating head and mask apparatus 50,except that an inline inner mask 72′ and an inline outer mask 74′ areused instead of the circular masks 72 and 74. The inline masks 72′ and74′ can also result in the same precise formation of the bus bars 22 asthe circularly rotating heating head and mask apparatus 50.

A variant of the inline heating head and mask apparatus 50′ is a dualbelt based inline heating head and mask apparatus 140 that is shown inFIGS. 10 c–10 e. The apparatus 140 comprises: 1) a work piece input area160, comprising a first belt 144, first rollers 158, and a first speedand tension adjuster 178, 2) a second belt 142, second rollers 156, anda second tension adjuster 176, and being driven by second motor 154,second motor pulley. 172, motor belt two 174, 3) a third belt 146, thirdrollers 162, and a third tension adjuster 182, and being driven by thirdmotor 152, third motor pulley 166, and motor belt three 168, 4) a thermospray area 150, 5) a work piece output area 170, comprising a fourthbelt 148, fourth rollers 162, and a fourth speed and tension adjuster184, and 6) an overspray removing device 190.

This inline apparatus 140 may also be practiced by employing other meansfor driving the belts, for example, sprocket gears and chains, racks andpinions, and the like, while still remaining within the scope and spiritof the present invention.

In operation, an incoming coated glass sheet 34 is conveyed by the firstbelt 144 to an adjustable stop 188. Note that the coating 44 is on aside of the coated sheet 34 that will make direct contact with thesecond belt 142. Note also that the stop 188 is capable of adjustment soas to position varying sizes of coated glass sheets 34 at the end of thefirst belt 144.

Upon reaching the stop 188, the coated glass sheet 34 is positionedinline with a roller area 198 that is between the second belt 142 andthe third belt 146 while centrally spanning the second belt 142. Thewidth of the second belt 142 is chosen to be less than the width of thesheet 34 so as to allow the second belt 142 to act as a mask whileexposing opposite edges of the coating 44 on the sheet 34.

Subsequently, a cylinder 199 causes an indexer 186 to urge the sheet 34into the roller area 198 between second belt roller 156 b and third beltroller 162 a so as to convey the sheet 34 in a direction toward thethermo spray area 150. Note that the linear speeds of the belts 142, 146being adjusted to be approximately the same by the respective adjusters176, 182 and that the sheet 34 is held in place by a clamping force thatis imposed by the opposing belts 142, 146. The cylinder 199 may berealized by any means that is conventional in the art to properly pushor pull the indexer 186.

Upon reaching the thermo spray area 150, the exposed opposite edges ofthe sheet 34 may be heated by at least one reducing flame 78 (not shownbut similar to those illustrated in FIGS. 10 a, 10 b)) and impinged byat least one metal feeding and heating devices 62, so as to disposemolten metal 64 onto the opposite edges of the coated sheet 34. The busbar deposition operation is accomplished in much of the same manner asthat used by the circular and inline heating head and mask apparatus 50,50′ and results in the deposition of the bus bars 22 at the oppositeedges of the coated glass sheet 32. Ceramic or glass-ceramic sheets mayreplace the glass sheets.

Following bus bar deposition in the thermo spray area 150, the sheet 34is conveyed to a fourth belt 148 having fourth belt rollers 164 andfourth speed and tension adjuster 184 and driven by a means (not shown)that is similar to the previously described motor, pulley, and belt,which in turn conveys the sheet 34 to a work piece output area 170.After drop-off of the sheet 34 onto the fourth belt 148, the second belt142 may be exposed to the overspray removing device 190 in order toremove any conductive metal overspray that may have been deposited onthe second belt 142. The overspray removing device 190 may be, forexample, a tank containing a coolant 196 and having an outlet 192 and aninlet 194, where the overspray is removed by thermal shock and scraping.However, the present invention may be practiced where the oversprayremoving device 190 is at least one fan, scraper, or the like.

The dual belt based inline heating head and mask apparatus 140 isdesigned to produce panels 20 in a fast and simple manner for heatingelements, for example, a so-called fifth burner appliance (like aseparate cooking appliance that would rest on a counter-top) and cooktopheating elements. In these applications a high speed, low cost processis advantageous and this apparatus 140 is capable of achieving thosegoals while producing high quality electrical connectivity to thecoating 44. However, this apparatus 140 may be used for producing panelsother than burner elements, for example, photovoltaic applications.

In the present invention, the masks 66, 66′, 72, 72′, 74, 74′, 142 maycomprise steel with a layer of chrome plating disposed on the steel.This has been found to inhibit the adhesion of copper and other metalsto the masks 66, 66′, 72, 72′, 74, 74′, 142 thus allowing a simplespring loaded scraper to continually clean the overspray from the masks66, 66′, 72, 72′, 74, 74′, 142 during production of the bus bars 22.This operation allows the overspray and dust of the conductive metal 56to be collected and re-sold. The present invention may further depositsoft electrically conductive materials (not shown) that include metaland metal oxides, often in combination with each other, onto the busbars 22, following bus bar deposition to the coating 44.

Examples of the soft conductive materials are silver based systems like(metal oxide/silver/metal oxide) and variants including double silverstacks and indium-tin-oxide (known as ITO.) All constructs of the busbars 22, metallic tabs 24 and the panels 20 that have been disclosedherein apply with the addition of the deposition of the soft conductivematerials.

The soft coatings may be deposited in a vacuum deposition process likethat produced by DC Magenetron Sputtering after the bus bars 22 aredeposited on the coatings 44. For example, these soft coatings may becopper traces that would conduct electrical current to electricalcomponents that would be mechanically attached to the glass sheet 32 orcoated glass sheet 34. An example electrical component would be acapacitive moisture sensing unit on the sheet 32, 34.

Another example of the present invention being used as an appliance isillustrated in FIG. 11, which is a perspective view of a warming oven100. The warming oven 100 would have at least a first warming shelf 106,however, FIG. 11 shows the warming oven 100 with the first warming shelf106 and an accompanying second warming shelf 108. The warming shelves106, 108 would comprise insulated glass panels 30, wherein the bus bars22 and metallic tabs 24 have been formed thereon in the manner describedabove in the present invention. The control of the warming of itemsplaced in the warming oven 100 would be accomplished by the ovencontrols 112, which would comprise the elements of the integratedconnection circuit 18.

An added advantage of the use of the insulated glass panel 30 in thewarming oven 100 is that the insulated glass panel 30 affords physicalseparation between the coating 44 and the item being thermo-conductivelywarmed, wherein capacitive coupling and leakage currents from theheating coating to the item being heated are virtually eliminated, thuseliminating electrical shock potential and spark ignition for a fire.

FIG. 12 illustrates another aspect of the present invention, where thereis shown an oven door panel 110, which is mounted in an oven door frame122 for viewing food items being cooked in an oven interior 124. Thisaspect of the present invention utilizes an assembly comprising atemperature sensing means, for example, rapid measurement of the voltageacross the bus bars 22 (as discussed above in conjunction with acontroller 16) or a temperature switch 118 disposed on the exterior ofthe coated glass sheet 34, with bus bars 22, for example, copper,disposed on the coating 44 (in the manners described above for thepresent invention), and a thermally activated light scattering material116 disposed on the coating 44. The light scattering material 116 maycomprise, for example, ThermoSEE™ which is commercially available fromPleotint LLC, West Olive, Mich.

The temperature switch 118 would be part of the integrated connectioncircuit 18 for the oven (not shown) and would function to sense theexterior temperature of the oven door panel 110. If the exteriortemperature of the oven door panel 110 would exceed a setpointtemperature, the temperature switch 118 would electrically open, whichin turn would cut off current (I) to conventional oven heating elements(not shown), so as to eliminate the possibility of burning a person thatmight touch the exterior surface of the oven door panel 110.

The bus bars 22, which may be connected to and controlled by theintegrated connection circuit 18, by way of the metallic tabs 24 thatare disposed on the bus bars 22 and electrically connected to thechannel conductors 27, are used to precisely control the heating of theoven door panel 110 so as to precisely control the opacity of the lightscattering material 116, which is opaque at room temperature and up to atemperature of about 150 degrees F., at which temperature and above, thelight scattering material 116 becomes essentially transparent. As aresult, the contents of the oven interior 124 can be viewed from outsideof the oven under the precise control of the integrated connectioncircuit 18 of the present invention or by conventional means in the art.

In accordance with the provisions of the patent statutes, the principlesand modes of operation of this invention have been described andillustrated in its preferred embodiments. However, it must be understoodthat the invention may be practice otherwise than specifically explainedand illustrated without departing from its spirit or scope.

1. A method of heating a glass panel, comprising: providing a glasspanel with a coating of a conductive doped metal oxide disposed thereon;impinging molten particles of copper at high velocity onto the coatingof the conductive doped metal oxide, thereby forming a copper bus barthat is in electrical connectivity with the coating of the conductivedoped metal oxide; and providing electricity to the copper bus bar,thereby heating the glass panel.
 2. The method of claim 1, wherein thecopper bus bar is in electrical communication with electrical componentsthat are physically disposed on the glass panel.
 3. The method of claim2, wherein the electrical components comprise at least one solar panelor a capacitive moisture sensing unit.
 4. The method of claim 1, whereina plasma gun or an oxyacetylene device is utilized for the impinging ofthe molten particles of copper at high velocity onto the coating.
 5. Themethod of claim 1, further comprising providing at least one circularlyrotating mask for shaping and sizing the copper bus bar.
 6. The methodof claim 1, further comprising providing at least one inline mask forshaping and sizing the copper bus bar.
 7. An electrically conductiveheated glass panel made by the method of claim 1, whereby the copper busbar has a metallic tab in electrical contact therewith, thus forming theelectrically conductive heated glass panel capable of ready connectionwith a source of electrical power.
 8. A method of heating a ceramicpanel or a glass-ceramic panel, comprising: providing a ceramic panel ora glass-ceramic panel with a coating of a conductive doped metal oxidedisposed thereon; impinging molten particles of copper at high velocityonto the coating of the conductive doped metal oxide, thereby forming acopper bus bar that is in electrical connectivity with the coating ofthe conductive doped metal oxide; and providing electricity to thecopper bus bar, thereby heating the ceramic or the glass-ceramic panel.9. A method of depositing a copper bus bar on a coating of a conductivedoped metal oxide disposed on a glass panel, comprising: masking an areaof a conductive doped metal oxide coating; heating the area of theconductive doped metal oxide coating with a reducing flame; feedingcopper into a metal feeding and heating device; melting the copper; andimpinging molten particles of the copper at high velocity onto the areaof the conductive coating, thereby depositing a copper bus bar on theconductive doped metal oxide coating.
 10. The method of claim 9, whereinat least one circularly rotating mask or at least one inline mask isutilized for masking and heating the area of the conductive coating withthe reducing flame.
 11. The method of claim 9, wherein the reducingflame comprises hydrogen.
 12. The method of claim 9, wherein thereducing flame comprises oxyacetylene.
 13. The method of claim 9,wherein the metal feeding and heating device comprises a plasma gun oran oxyacetylene device.
 14. The method of claim 9, wherein the heatingcomprises imparting a temperature of about 500 degrees F. to the area ofthe conductive coating under stoichiometric conditions, whereby acombination of oxygen with the molten copper is controlled.
 15. Themethod of claim 9, further comprising shaping and sizing of the copperbus bar.